As wireless network data rates improve using third generation (3G), fourth generation (4G), and WiFi technologies, more and more bandwidth-intensive applications are being developed. A 4G wireless network is an all Internet protocol (IP) wireless network in which different advanced multimedia application services (e.g., voice over IP (VoIP) content, video content, etc.) are delivered over IP. 4G wireless networks include a radio access network (e.g., a long term evolution (LTE) network or an enhanced high rate packet data (eHRPD) network) and a wireless core network (e.g., referred to as an evolved packet core (EPC) network). The LTE network is often called an evolved universal terrestrial radio access network (E-UTRAN). The EPC network is an all-IP packet-switched core network that supports high-speed wireless and wireline broadband access technologies. An evolved packet system (EPS) is defined to include the LTE (or eHRPD) network and the EPC network.
A typical LTE network includes an eNodeB (eNB) and network nodes, such as a mobility management entity (MME), a serving gateway (SGW), and a packet data network (PDN) gateway (PGW). User equipment (UE) may connect to an appropriate eNB in a LTE network based on signal strength. The eNB forwards a request to the MME to select a SGW and a PGW, as well as a backup SGW and a backup PGW, based on querying a domain name system (DNS) that is manually configured with static mappings.
The MME utilizes recursive DNS queries to select the closest (e.g., based on physical distance) or most appropriate network nodes (e.g., SGW and PGW) to serve the UE. The DNS is provided in the network architecture to manage an addition or a change of these network nodes from the network. The Third Generation Partnership Project (3GPP) defines a format of a fully qualified domain name (FQDN) record to be used by the MME for the network node selection process. For example, the 3GPP states that the home network realm/domain shall be in the form of:                epc.mnc<MNC>·mcc<MCC>.3gppnetwork.org,where the <MNC> and <MCC> fields correspond to a Mobile Network Code (MNC) and a Mobile Country Code (MCC) of an operator's public land mobile network (PLMN). Both the <MNC> and <MCC> fields are three digits long. If the MNC of the PLMN is two digits, then a zero may be added at the beginning. An example FQDN record may include the following format:        topon.lb1.PGW01.HLLS.SA001.WE.node.epc.mncXXX.mccXXX.3gppnetwork.org.        
Currently, the MME can only store a limited number of FQDN records having such formats. The limited storage capability of the MME limits the number of FQDN records from which the MME may select. Accordingly, the limited storage capability of the MME limits a number of network nodes from which the MME may select for communication sessions with UEs.